Fish aquaculture is well known and forms an established industry in many different countries. Known systems generally rely on the use of cages for raising fish, in which the feeding of the fish is controlled using various types of known feeding devices which can either be automated or manually operated.
Generally speaking, fish “farms” are located in relatively quiet harbour conditions where the weather and ocean environments are not severe as in an open ocean location. The use of such aquaculture systems under relatively calm conditions (i.e. free from wind, current, wave action, etc.) is desirable in order to minimize potential damage to equipment and to provide for controlled feeding.
With the growing aquaculture industry, many of the relatively good locations (such as quiet harbours) are reaching the point of saturation in terms of the capability of such harbours handling a given number of aquaculture systems; in other cases, the harbours under certain conditions are becoming polluted by the effluent from the aquaculture farming, and in still further situations, the increasing number of aquaculture systems is creating a problem for the use of harbours for ship, boat or similar traffic in terms of potential collisions between such traffic and anchored fish cages.
It has also been found in recent studies that placing aquaculture cages in water there is an active movement of the water can be desirable in terms of raising fish. Not only does the flow of water aid in the dispersal of effluent, but it appears to have beneficial effects on the raising of fish.
With modern technology, fish farms using cages often have very large fish populations in such cages—typically 50,000 to more than 100,000 fish can be raised under controlled conditions in a single cage. The amount of food required for such a large fish population poses another problem for the aquaculture industry, since feed supply systems must be continuously refilled or ready access to individual cages using manual feeding systems has to be provided for.
It would be desirable to develop and aquaculture system which would not be restricted to areas such as harbours but rather, could be located in the open ocean under controlled conditions which would permit raising of fish in a manner similar to that employed in protected areas such as harbours. One of the problems that would be created using an open ocean environment for the fish cages is the fact that ocean currents could cause severe problems for a successful operation; it has been found that when fish are exposed to strong flowing current conditions, the fish population can die. While limited amounts of current are desirable, excessive current is undesirable. Moreover, any ocean aquaculture system would have to be structurally designed so as to permit several fish cages to be contained within a defined area, yet permitting the plurality of cages to adapt to different current conditions when currents change. This would require a freely movable system anchored generally at a fixed point, which system could be rotatable or movable about such a fixed point.
Moreover, any ocean aquaculture system would have to be designed in such a manner that wave conditions, as well as wind conditions, would have a minimal effect on the aquaculture system, particularly for feeding or food distribution amongst several fish cages. Under quiet harbour conditions, exposure of the upper portions of fish cages would not be a detrimental factor. But, under open ocean conditions, waves or wind can cause damage to such systems.
When considering ocean aquaculture systems, other weather conditions such as freezing rain, snow, and the like must also be take into consideration, particularly when employing an automated feeding system. Under certain conditions, the build-up of ice on an ocean system, particularly on a feed distribution system, could be disastrous in terms of maintaining fish under healthy conditions.